1. Field of the Invention
The present invention relates to an image data distribution system and method of distributing image data to a plurality of image communication units connected thereto through a network.
2. Description of the Prior Art
FIG. 21 shows a typical network arrangement of the prior art image data distribution system (facsimile broadcast system). In this example, a document (image data) is sent from the facsimile unit 1002 at the head office to facsimile unit 1003 at branch office A, facsimile unit 1004 at branch office B and facsimile unit 1005 at branch office C. The system works the following way.
The facsimile unit 1002 at the head office reads a document as destination group member numbers are specified. The destination group member numbers and the document are then sent to a facsimile data distribution exchanger 1001. The image data sent is first stored in storage means such as a hard disk (not shown).
The facsimile data distribution exchanger 1001 has a list of facsimile numbers—the facsimile numbers of the facsimile unit 1003, the facsimile unit 1004 and the facsimile unit 1005—corresponding to the destination group member numbers. The facsimile data is distributed to the facsimile units of the group members one after another at those facsimile numbers given in the list. That is, the facsimile data distribution exchanger 1001 sends the image data stored in the storage means to the facsimile unit 1003 at branch office A the facsimile unit 1004 at branch office B and the facsimile unit 1005 at branch office C one after another though the public switched telephone network 1000.
That way, one and the same data is transmitted to a plurality of facsimile units from the facsimile unit 1002 of the head office.
In case the facsimile data distribution exchanger 1001 is connected with the public switched telephone network 1000 through a plurality of circuit lines, the same data can be sent to a plurality of facsimile units simultaneously through those circuit lines and the public switched telephone network 1000.
Meanwhile, when a new branch facsimile unit is to added to the list of the destinations, the list of the group member numbers or branch numbers in the facsimile data distribution exchanger 1001 is revised or changed. With the prior art image data distribution system—the facsimile broadcast system—, there arose a variety of inconveniences in the process of changing the list. For example, the necessary work had to be done by the user—the system operator or the like himself or herself. The procedure was very troublesome and allowed no mistake in inputting facsimile numbers. Otherwise, the system would not work normally and image data would not be delivered to the intended facsimile unit. In addition, the changes in the list were not be reflected automatically in the respective facsimile units, and the system operator himself or herself had to notify each branch of the changes effected.
Furthermore, the facsimile broadcast system which used the public telephone circuits and the facsimile communication protocol for transmission of image data, presented such problems as long communication time, high costs and low resolution or poor image quality.